1. Field of the Invention
The present invention relates to a substrate conveyer and, more particularly, to a substrate conveyer which conveys a substrate in a vacuum processing apparatus, and a vacuum processing apparatus having the substrate conveyer.
2. Description of the Related Art
An inline vacuum processing apparatus is configured to convey a substrate to each chamber and sequentially perform predetermined vacuum processes, while the substrate is held by a carrier. The carrier is equipped with a permanent magnet, whereas a magnetic screw is rotatably disposed on the chamber side to be separated from the vacuum atmosphere in each chamber by a vacuum seal. Magnetic poles with opposite polarities are alternately generated on the surface of the magnetic screw in a spiral pattern. A substrate conveyer is configured to form magnetic coupling between the portion magnetized in a spiral pattern, and the permanent magnet of the carrier, thereby moving the carrier with rotation of the magnetic screw (see, for example, Japanese Patent Laid-Open Nos. 2004-218844, 5-49232, and 5-52248).
Japanese Patent Laid-Open No. 2000-032733 discloses a flat motor including a movable element having a magnet, and a stator (base body) having an armature coil. The stator is arranged in a vacuum chamber, which has an upper portion formed by a flat ceramic plate, and a lower portion formed by a stator yoke. The movable element is arranged on the ceramic plate of the stator via an air slider, and can move on the ceramic plate. A substrate table is arranged on the movable element.
To improve the efficiency of a motor including a vacuum partition wall arranged between the magnet of the movable element and that of the stator, the thickness of the vacuum partition wall is desirably reduced. On the other hand, as the thickness of the vacuum partition wall reduces, its strength may decrease.